1. Field
The present disclosure relates to multi-channel fluorescence detecting modules and nucleic acid analysis systems including the multi-channel fluorescence detecting modules, and more particularly, to multi-channel fluorescence detecting modules and nucleic acid analysis systems capable of analyzing nucleic acid samples disposed on microfluidic device cartridges in real time by using the multi-channel fluorescence detecting modules including a linear actuator.
2. Description of the Related Art
With the advance of point-of-care technology, there is increasing interest in gene analysis, in vitro diagnosis, and gene sequence analysis, and demand therefor is also increasing. Platforms and systems for rapidly performing a large amount of analysis using small amounts of samples have been developed and introduced into the market. For example, there is interest in microfluidic devices or platforms such as lab-on-a-chip devices. Such a microfluidic device includes a plurality of microfluidic channels and chambers to control and process a small amount of a fluid. The use of microfluidic devices reduces time periods of microfluidic reactions and allows microfluidic reactions and measurements of the microfluidic reactions to take place at the same time. Such microfluidic devices are manufactured by various methods, and various materials are used according to the manufacturing methods.
For example, in a gene analysis, a sample may be refined/extracted and amplified to obtain a sufficient amount of sample for analyzing whether the sample has a certain kind of DNA or precisely detecting the amount of a certain kind of DNA. For example, polymerase chain reaction (PCR) is most widely used among the various gene amplifying methods. A fluorescence detection method is widely used for detecting DNA amplified by PCR. In quantitative real-time PCR (qPCR), a plurality of fluorescent dyes/probes and a set of primers are used to amplify a target sample and detect/measure the amplified target sample in real time.
In qPCR using TaqMan probes, TaqMan probes separated from templates in a DNA amplifying stage become fluorescent. That is, as qPCR proceeds, the number of TaqMan probes separated from templates is exponentially increased, and thus the level of a fluorescence signal is also exponentially increased. Therefore, a target sample may be detected or quantitatively analyzed by measuring variations of the level of such a fluorescence signal. As the number of PCR cycles increases, the shape of a fluorescence signal curve follows an S-curve, and a point at which the shape of the fluorescence signal curve is largely varied is measured and determined as a threshold cycle (Ct). qPCR platforms for in vitro diagnosis, gene analysis, bio marking, and gene sequence analysis have been commercialized.
In the case of nucleic acid analysis systems of the related art using step motors, a transfer module may scan only a single cartridge because the positional precision and driving speed of the step motors are limited. Therefore, in order to analyze nucleic acids for a plurality of cartridges, a plurality of transfer modules on which fluorescence detecting modules are respectively disposed are used. That is, nucleic acid analysis systems of the related art include as many transfer modules and fluorescence detecting modules as the number of cartridges to be analyzed at a time. In the related art, as a result, it is difficult to reduce the size of nucleic acid analysis system. In addition, since a plurality of fluorescence detecting modules including expensive optical components are used, it is difficult to reduce the manufacturing costs of nucleic acid analysis systems of the related art. Furthermore, the use of a plurality of step motors results in a large amount of noise.